The prior art (U. M. Dzhemilev, A. G. Ibragimov, A. P. Zolotarev, L. M. Khalilov, R. R. Muslukhov, Synthesis and conversion of metallocycles. Synthesis of polycyclic alumacyclopentanes involving (η5-C5H5)2ZrCl2. Izv. AN, Ser. Khim., 1992, no. 2, pp. 386-391) relates to a method of obtaining tricyclic AOC, specifically, 3-ethyl-3-alumatricyclo[5.2.1.02,5]decane (2) by a reaction of norbornen with triethylaluminum (Et3Al) under the action of a catalyst zirconacendichloride (Cp2ZrCl2) in hydrocarbon solvents at a temperature of ˜25° C. for 12 to 14 hours in accordance with the scheme:

The method is insufficient for obtaining exo-tricyclo[4.2.1.02,5]non-7-en-3-spiro-1′-(3′-ethyl-3′alumina)cyclopentane of the general formula (1).
The prior art (U. M. Dzhemilev, A. G. Ibragimov, A. P. Zolotarev, L. M. Khalilov, R. R. Muslukhov, Synthesis of polycyclic alumacyclopentanes involving (Cp2ZrCl2. Izv. AN, Ser. Khim., 1992, no. 2, pp. 386) relates to a method of obtaining tri- and tetracyclic AOC, specifically, 3-ethyl-3-aluminatricyclo[5.2.1.02,6]dec-8-en (3) and 3,9-diethyl-3,9-dialuminatetracyclo[5.5.1.02,6.08,12]tridecane (4) at a ratio of ˜2:8 with the integrated yield ˜75% by a reaction of norbornadiene en with triethylaluminum taken at a mole ratio of 1:2 in the presence of 3 to 5 mol % of Cp2ZrCl2 at a temperature of ˜20° C. for 12-14 hours in accordance with the scheme:
The method is insufficient for obtaining exo-tricyclo[4.2.1.02,5]non-7-en-3-spiro-1′-(3′-ethyl-3′alumina)cyclopentane of the general formula (1).
Thus there are no published data on the synthesis of exo-tricyclo[4.2.1.02,5]non-7-en-3-spiro-1′-(3′-ethyl-3′alumina)cyclopentane of the general formula (1).